A third inmate, Wayne Buckingham, who thwarted their alleged plan by telling authorities, told the Supreme Court on Thursday that Walkuski knew where Judge Rice had coffee and wanted to walk up and "give him both barrels".

"It was at a table outside a coffee shop in an arcade," Buckingham said.

"He (Walkuski) said ... 'I'd like to get a trench coat, cut the hole out of the pocket, put my shotty inside the trench coat, walk up to him ... and just pull the coat open, pull the shotgun out and go bang, bang.